Effect of continuous renal replacement therapy on all-cause mortality in COVID-19 patients undergoing invasive mechanical ventilation: a retrospective cohort study

Yi Yang; Jia Shi; Shuwang Ge; Shuiming Guo; Xue Xing; Yanan Wang; Anying Cheng; Qingquan Liu; Junhua Li; Yong Ning; Fan He; Gang Xu

East Respiratory Syndrome coronavirus (MERS-CoV). 2 As of March 9 th , 2020, COVID-19 has infected more than 100,000 people worldwide and caused more than 3,500 deaths, and the data are still increasing; in Wuhan, the fatality rate of COVID-19 was 4.8% (2404/49965). Of note, critically ill patients with COVID-19 have a high mortality rate. In a study of 52 critically ill patients in Wuhan, 32 (61.5%) patients died at 28 days and the mortality rate was 81.1% (30/37) in patients requiring mechanical ventilation. 3 Accumulated evidence has strongly demonstrated that systemic inflammatory response, acute kidney injury (AKI) and fluid overload (FO) were associated with high mortality in severe sepsis. [4] [5] [6] In critically ill patients with COVID-19, the overwhelming inflammation including C-reactive protein (CRP) and interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor α (TNF-α) were observed, 7-10 which is consistent with patients suffering from SARS-CoV 11 and MERS-CoV. 12 Continuous renal replacement therapy (CRRT) is a great help in critically ill patients not only to control of electrolyte, acid-base derangements but also to remove inflammatory mediators and improves oxygenation in fluid overload. [13] [14] [15] CRRT has been applied to critically ill patients, including patients with SARS-CoV, MERS-CoV and other viral infectious diseases such as Ebola virus disease. 14, 16 However, the benefits of CRRT are still no consistent conclusion in critically ill patients. 17 CRRT significantly reduced the level of IL-6 and decreases hospital mortality rate in pediatric severe sepsis, especially in patients with acute respiratory distress syndrome (ARDS). 18 Besides, a meta-analysis revealed that patients who received CRRT had significantly lower mortality compared to conventional therapy. 19 Hoverer, CRRT was associated with increased mortality in patients with MERS-CoV. 16 The relationship between CRRT and patients' outcome varied in patients with the different disease and was effected by the modalities, anticoagulation, vascular access management, timing of initiation and intensity of CRRT. 17, 20, 21 To date, no specific treatment has been confirmed to be effective for COVID-19, and supportive treatment remains essential. As far as we know, the effect of CRRT on critically ill patients with COVID-19 has not been reported. In this retrospective cohort study, we aimed to explore the effect of CRRT on all-cause mortality in patients with COVID-19 undergoing invasive mechanical ventilation and the risk factors for mortality in patients with CRRT treatment.